The X-ray Structures of 2- and 3-Sulfolene and Two Halogenated Derivatives

Abstract The structures of the isomeric 2,5-dihydrothiophene 1,1-dioxide [orthorhombic, a = 11.340(2), b 7.0887(15), c 6.2811(13) Å, space group Pnma ] and 2,3-dihydrothiophene 6.3903(13), 7.2783(16), 11.075(2) have been determined show perfectly planar rings with expected bond lengths angles. In contrast, halogenated derivatives 3,3,4,4-tetrachlorotetrahydrothiophene [monoclinic, 11.8716(8), 6.5579(4), 11.4802(8) β 97.705(17), P 2 1 /c] 2,3-dibromotetrahydrothiophene 5.2502(3), 11.3561(6), 24.9802(17) Pbca both twisted conformations. degree planarity is compared that in comparable 5-membered ring cyclic sulfones C–H…O hydrogen bonding patterns are discussed for all four structures. Graphical two sulfolenes while tetrachloro- dibromo-derivatives adopt